create a vehicle hire company

What i have to do is create a vehicle hire company. The programshould allow you to enter cars and vans (both with differentattributes), allocate a vehicle to a customer, display the vehicleinformation etc... i have got so far in the program but i am nowgetting confused.

I have implemented a MVC (model view controller) stucture to theassignment. however inside my controller i am creating one instanceof vehicle (with no args) and then further down i am adding a car tothe vehicle class.

The reason i am confused is because in my vehilce class i am creating2 vectors to store the cars and the vans in (car and van classesinherit from vehicle) but i want to be able to store both vans andcars into one vector and then later determine what the object type isi.e. instanceof to display the information to screen. i am not sureif i should be creating more that one vehicle class i.e. a vehicleclass for each car/van or what ?

what about polymorphism could this be used in the program. here is abit of code from different classes.

VEHICLE CLASS

public void initialise() {carVector = new Vector(1,1);vanVector = new Vector(1,1);}